A/Ding at last

In my travels around the net looking for information regarding the A/D converter, I came across several examples. I have now distilled them into one simple example of software-driven A/D conversion, which can be found here. The program initializes channel 1 on AD Converter 0 for software-driven A/D with 10 bits of accuracy. The function ADC_Read powers on A/D Converter 0 and starts the conversion. When the conversion is "Done," A/D Converter 0 is powered down again (gotta save those batteries).

I have hacked the script that changes the voltage on an input pin to make that pin AD01. You can start the script running using the Analog ON button in the toolbox when you are in the uVision debugger. If you run this example, you can see the value of the Analog Input AD01 changing, and the result of the A/D conversion shows up in the RESULT portion of the A/D Global Status Register. The RESULT also appears as a 10 bit number in the result variable in the debugger watch window. Just for fun, I added the AD01 input and the result variable to the Logic Analyzer and you can see these values change in step. This sort of thing would be useful if there were long delays between reading the A/D, in which case the result graph would become more a series of steps than a straight line, and it would be easy to determine what data was being lost between sampling of the analog input.